PRACTICAL ORGANIC CHEMISTRY hydrin. Yield of dichlorhydrin about 120 grams. Epichlor- hydrin is obtained by the action of aqueous potash solution upon the dichlorhydrin. A solution of 100 grams of caustic potash in 200 c.c. of water is well cooled and poured slowly, with constant stirring, into the dichlorhydrin. Rise of temperature must be carefully avoided. The epichlorhydrin is separated from the product by adding ether, which dissolves out the epichlorhydrin. The upper layer is separated, shaken up with a little water, and again separated. It is then dehydrated over calcium chloride and decanted into a round flask. The ether is first removed on the water-bath. The residue is then fractionally distilled. This is effected by attaching a fractionat- ing column to the flask (see p. 137). The portion boiling at 115 — 125° is epichlorhydrin, and is collected separately. The portion boiling above this temperature consists mainly or acetodichlorhydrin. Yield 25 — 30 grams. CH2OH.CI-IOII.CHoOH + HC1 = CH2C1.CHOH.CH2OH + H20. a-Monochlorhydrin. CH2CLCHOH.CH2OH + HC1 = CH2C1.CHOH.CH2C1 + H20. aa-Dichlorhydrin. CH2Cl.CHOH.CH2Ci + KOH = CHCKLCHoCl + KC1 + H20. Epichlorhydrin. Properties. — Mobile liquid, with an ethereal smell ; b. p. 117°; sp. gr. 1-203 at o°. Reaction. — Warm a little of the epichlorhydrin with caustic potash solution. It dissolves, forming glycerol. See Appendix^ p. 260. CH(OH).COOH Malic Acid, | CH2.COOH Malic acid is prepared from the juice of the mountain ash berries by precipitation as the calcium salt. Properties. — It is soluble in water and alcohol, but not in ether. On heating, it loses water and is converted into fumaric and maleic acids (see p. 125). On oxidation it gives malonic acid and on redaction succinic acid. Reactions. — r. Make a strong neutral solution, add calcium chloride solution and boil. The calcium salt is precipitated.